How dung beetles can help keep waterways clean

Holding dung beetles are Columba College pupil Megan Hanning, 16, Dr Shaun Forgie of Dung Beetle Innovations and John McGlashan deputy head boy Robert Millar, 17. Photos / Linda Robertson

"It's time for the dung beetle".

So says Dr Shaun Forgie, who admits he has been obsessed with the critters since the early 1990s.

But it was not until 2011 that an application to import 11 different scarab species — suitable for all New Zealand climatic conditions — was approved.

Dr Forgie, the co-founder of Auckland-based Dung Beetle Innovations, was in Dunedin on Friday to speak at a dung beetle seminar at John McGlashan College.

That was followed by the release of about 1500 beetles on a Taieri property which was planned to improve soil health and structure.

By doing that, there would be an 80 per cent reduction in surface flow of contaminants into waterways from pasture, he said.

Dung beetles were a sustainable solution which would alleviate pressure on other mitigation tools such as fencing and riparian planting and he believed they were the "best tool out there".

Beetle tunnelling reduced soil compaction and increased aeration. Dung burial resulted in increased grass root growth, leading to better retention of dung and urine in the soil.

A close-up of a dung beetle prior to its release on a Taieri farm.

That cycle reduced sediment and microbial contamination in run-off, reduced leachate pollution, improved pastoral production and ultimately protected the quality of waterways.

The beetles' release was the "perfect case study" for agribusiness pupils from John McGlashan College and Columba College, John McGlashan head of agribusiness Dr Craig Preston said.

Once established, they would provide pupils a long-term study over the next few years as they watched the beetles "change" the land.

Three years ago, John McGlashan and Columba College collaborated as lead schools in setting up a centre of excellence for agricultural science and business, and delivering an agribusiness course across both school campuses.

The initiative was the brainchild of St Paul's Collegiate School in Hamilton, which joined with agricultural industry partners in the aim of delivering an agribusiness programme to secondary schools throughout New Zealand.

Columba agribusiness teacher Sam Doran taught the economics and business side, while Dr Preston taught the "sciency stuff".

Dr Preston called it an "absolutely fantastic" programme which looked at careers outside the farm gate.

Classes were full and there were more pupils than there was room for those wanting to take part. At this stage, there was a year 12 class and a year 13 class but there was potential for two classes to be offered in each year group.

Last year, the University of Otago announced a new major within applied sciences, having the aim of developing future leaders in agriculture to help drive the industry forward.

The field of "agricultural innovation" was designed to focus students' learning on major issues and innovative solutions.

Dr Preston was excited about the move, saying some of the agribusiness classes' former pupils had enrolled in it.

There was a desire to "give back" to all those parties that had been involved with the programme, which was not classroom-bound, and a group of farmers and parents attended the seminar and release.